The parallel postulate- given a line and a point not on the line, there is one and only one line that contains the given point and is parallel to the given line
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Triangle sum theorem- the sum of the measures the angles of a triangle are 180

Exterior Angle Theorem- the measure of an exterior angle of a triangle is equal to the sum of the meaures of the remote interior angles
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Great Circle is a circlethat lies in a plane that passes through the center of the sphere

The angles of the polygon at the other vertices are called Remote interior angles

Parallel Postulate Example:

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Examples
9. m<A= 45 degrees, m<B=degrees, M<3=90 degrees Answer: m<B=45 degrees
11. m<X=90 degrees, m<Y=degrees, m<Z=90 degrees Answer: m<Y=No such triangle exists